Permeation of lanthanides across flat sheet supported liquid membrane containing CMPO as a carrier extractant

Octyl(phenyl))-N,N-diisobutyl carbamoylmethyl phosphine oxide is a well known ligand and has been extensively studied for trivalent actinide extraction. The ligand shows excellent extraction of trivalent actinides in the acid range of 1 – 6 M HNO₃. Since 0.2 M CMPO in n-dodecane, a composition proposed for actinides partitioning, forms third phase when contacted with acid solution, 1.2 M TBP is also added in CMPO phase as a phase modifier. However, presence of 1.2 M TBP phase facilitates the extraction of large amount of acid in the organic phase which in terms creates problem in back-extraction of the metal ions. In order to avoid this problem, studies have been performed to evaluate other phase modifiers with CMPO. Recently it has been shown that using iso-decanol as a phase modifier gives better performance of CMPO phase when compared with TBP as a phase modifier. Needless to mention, all the studies with CMPO and iso-decanol system have been performed by solvent extraction. An attempt has been made in the present work to explore the use of CMPO and iso-decanol solvent in liquid membrane for the separation of lanthanides. In a first attempt, optimization of the solvent phase was done in solvent extraction by measuring the distribution ratio of Eu³⁺ (DEu) form 3 M HNO₃ at different composition of CMPO (0.1 – 0.4 M) and isodecanol (5 – 10 %) in n-dodecane